The effect of phosphate supply on the growth and botanical composition of annual type pasture

1964 ◽  
Vol 15 (1) ◽  
pp. 61 ◽  
Author(s):  
RC Rossiter
Keyword(s):  
Field Experiments ◽  
Total Yield ◽  
Indirect Evidence ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Residual Effects ◽  
Phosphate Deficiency ◽  
Phosphate Supply ◽  
High Phosphate

The results of two long-term field experiments and two 1-year experiments are reported. In three of these, severe phosphate deficiency was present initially. At high phosphate supply, the annual total yield was not significantly related to age of pasture over periods of 10–13 years. At intermediate and low supply, yields relative to high phosphate supply increased significantly with time; these increases are believed to demonstrate residual effects of phosphate. Indirect evidence for nitrogen accretion from clover under severely phosphate-deficient conditions is presented. Sward components—in the long term—responded differentially to phosphate supply. With very low phosphate, erodium (Erodium botrys (Cav.) Bertol.) and flatweed (Hypochoeris glabra L.) were dominant; whereas with high phosphate, cape-weed (Cryptostemma calendula (L.) Druce) and ripgut brome grass (Bromus rigidus Roth)—or else barley grass (Hordeum leporinum Link)—were dominant. Subterranean clover (Trifolium subterraneum L.), though present under these extremes, was relatively more plentiful at intermediate levels of supply. However, at "steady state" conditions, the range in clover content was fairly narrow (from c. 20 to 40%). The significance of these findings to a sheep infertility problem ("clover disease") of subterranean clover-dominant pastures is discussed.

Comparing different sources of sulfur for high-rainfall pastures insouth-western Australia

2003 ◽  
Vol 43 (10) ◽  
pp. 1221 ◽  
Author(s):  
M. D. A. Bolland ◽  
J. S. Yeates ◽  
M. F. Clarke
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Residual Value ◽  
Single Superphosphate ◽  
Pasture Production ◽  
Leaching Losses ◽  
S Deficiency ◽  
Different Sources

The dry herbage yield increase (response) of subterranean clover (Trifolium subterraneum L.)-based pasture (>85% clover) to applications of different sources of sulfur (S) was compared in 7 field experiments on very sandy soils in the > 650 mm annual average rainfall areas of south-western Australia where S deficiency of clover is common when pastures grow rapidly during spring (August–November). The sources compared were single superphosphate, finely grained and coarsely grained gypsum from deposits in south-western Australia, and elemental S. All sources were broadcast (topdressed) once only onto each plot, 3 weeks after pasture emerged at the start of the first growing season. In each subsequent year, fresh fertiliser-S as single superphosphate was applied 3 weeks after pasture emerged to nil-S plots previously not treated with S since the start of the experiment. This was to determine the residual value of sources applied at the start of the experiment in each subsequent year relative to superphosphate freshly-applied in each subsequent year. In addition, superphosphate was also applied 6, 12 and 16 weeks after emergence of pasture in each year, using nil-S plots not previously treated with S since the start of the experiment. Pasture responses to applied S are usually larger after mid-August, so applying S later may match plant demand increasing the effectiveness of S for pasture production and may also reduce leaching losses of the applied S.At the same site, yield increases to applied S varied greatly, from 0 to 300%, at different harvests in the same or different years. These variations in yield responses to applied S are attributed to the net effect of mineralisation of different amounts of S from soil organic matter, dissolution of S from fertilisers, and different amounts of leaching losses of S from soil by rainfall. Within each year at each site, yield increases were mostly larger in spring (September–November) than in autumn (June–August). In the year of application, single superphosphate was equally or more effective than the other sources. In years when large responses to S occurred, applying single superphosphate later in the year was more effective than applying single superphosphate 3 weeks after pasture emerged (standard practice), so within each year the most recently applied single superphosphate treatment was the most effective S source. All sources generally had negligible residual value, so S needed to be applied each year to ensure S deficiency did not reduce pasture production.

Increased seed production of subterranean clover pastures in response to fertilizers supplying calcium

1974 ◽  
Vol 14 (71) ◽  
pp. 749 ◽  
Author(s):  
PG Ozanne ◽  
KMW Howes
Keyword(s):  
Seed Production ◽  
Calcium Concentration ◽  
Field Experiments ◽  
Seed Set ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Unit Weight ◽  
Gypsum Plaster ◽  
Total Seed ◽  
Seed Yields

The effects of four common fertilizers containing calcium on seed production in subterranean clover (Trifolium subterraneum) were measured at six locations over five years in a total of fifteen field experiments. Calcium as a sulphate, carbonate or phosphate salt was applied to subterranean clover pastures either at the start of the growing season (autumn) or at flowering (spring). Gypsum, plaster of Paris, or lime gave large increases in seed yield per unit area and also per unit weight of tops. Spring applications of superphosphate increased seed yields in only two out of four experiments. Gypsum applied in spring at 200-500 kg ha-1 was as effective as 2,000 kg ha-1 of lime applied in autumn. Applications of lime in spring were much less effective. Increased seed yields were due to increases in burr yield, seed number per burr, and mean weight per seed. They were usually accompanied by increases in calcium concentration in the seed. Responses in seed production to calcium applications were obtained in all three sub-species of Trifolium subterraneum. In two experiments, newly sown on a soil type on which subterranean clover regeneration and persistence is commonly very poor, applied calcium doubled or quadrupled seed set. In 13 experiments using soils on which subterranean clover had persisted as the major component of the pasture for several years, calcium in the year of application increased the total seed bank by 6 to 31 per cent, and the current seed set by a greater amount.

Growth of skeleton weed (Chondrilla juncea L.) as affected by growth of subterranean clover (Trifolium subterraneum L.) and infection by Puccinea chondrillina Bubak and Syd

1975 ◽  
Vol 26 (6) ◽  
pp. 975 ◽  
Author(s):  
RH Groves ◽  
JD Williams
Keyword(s):  
Leaf Area ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Root Competition ◽  
Leaf Number ◽  
Root Weight ◽  
Large Reduction ◽  
Plant Parts ◽  
Chondrilla Juncea

Growth of skeleton weed (Chondrilla juncea, form A) and subterranean clover (Trifolium subterraneum) was studied in a glasshouse experiment in which the species were grown alone or together and the resultant effects of shoot and root competition assessed. The leaf number and weight of plant parts of C. juncea were reduced by competition vith subterranean clover, especially when shoots of the two species were competing. The leaf area of C. juncea was reduced, especially when roots of the two species were growing together. Puccinia chondrillina on C. juncea rosettes reduced leaf number, leaf area, and weight of plant parts. Subterranean clover grown with C. juncea infected with P. chondrillina further reduced the size and weight of the weed. The large reduction in leaf area and root weight of C. juncea (form A) plants in the presence of both subterranean clover and P. chondrillina suggests that growth of this form of C. juncea in Australia will be greatly reduced in pastures containing these species. In the long term, densities of this form may possibly be so lowered that a significant level of control will be reached in a cereal cropping-pasture system.

Studies on nodulation responses to pelleting of subterranean clover seed.

1961 ◽  
Vol 12 (4) ◽  
pp. 578 ◽  
Author(s):  
JA Thompson
Keyword(s):  
Seed Coat ◽  
Field Experiments ◽  
Chemical Constituents ◽  
Chemical Properties ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Coating Materials ◽  
Physical Separation ◽  
Clover Seed

In a series of field experiments on seven soils of pH 6.0 or higher, nodulation of subterranean clover (Trifolium subterraneum L. var. Tallarook) was improved by pelleting the seed with various glues and coating materials, prior to inoculation with dry peat inoculum. On these soils the responses were not related to the chemical properties of the pellet materials. The beneficial effect was apparently the result of physical separation of the seed coat and inoculum. It is postulated that pelleting of seed protects the inoculum from an antibiotic, whlch has been found in subterranean clover seed coats, and which is active against Rhizobium in culture. On a soil of pH 5.1 a nodulation response to two types of pelleting materials was apparently related to the chemical constituents of the coating materials. In this soil there was less evidence of the importance of physical separation of the inoculum from the seed coat. It seems likely that soils may differ considerably in their ability to inactivate the antibiotic. Nodulation was not improved by in situ fumigation, prior to sowing, of two soils of pH 6.0 and 6.6, which indicated that antagonism by soil microorganisms was not the cause of poor nodulation in these soils. Significant nodulation responses to pelleting were obtained in sowings in these fumigated soils.

Infection of subterranean clover swards with bean yellow mosaic potyvirus: losses in herbage and seed yields and patterns of virus spread

1994 ◽  
Vol 45 (7) ◽  
pp. 1427 ◽  
Author(s):  
RAC Jones
Keyword(s):  
Field Experiments ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Yield Losses ◽  
Grazing Experiment ◽  
Growing Seasons ◽  
Heavy Grazing ◽  
Herbage Yield ◽  
Seed Yields ◽  
Grazed Swards

During 1989-92, subterranean clover ( Trifolium subterraneum L.) was grown in field experiments in which swards of six cultivars were infected with bean yellow mosaic potyvirus (BYMV) by transplanting small BYMV-infected subterranean clover plants into them. The swards were then grazed by sheep or mown to simulate grazing. The infected transplants were the primary virus source for subsequent spread by aphids. Spread initially centred on infected transplants resulting in circular expanding infected patches. Later, secondary patches, isolated affected plants and more generalized infection sometimes developed. The extent of spread within swards from the transplants varied with cultivar, BYMV isolate, site and year. Final BYMV incidence ranged from 12% of plants symptom-affected by isolate MI in cv. Junee in 1991 to 100% by isolate SMB in cv. Leura in 1992. BYMV spread mostly occurred in spring and was increased around the edges of areas of bare ground in swards. In two experiments at one site in which 'mini swards' of cvv. Green Range, Karridale and Leura were mown repeatedly, BYMV-infection decreased herbage yields (dry weights) by 12-16% while seed yields were decreased significantly (by 37-40010) in one experiment. In a grazing experiment at a second site with swards of cvv. Esperance and Karridale, BYMV-infection decreased overall yields of herbage by 18-39% and seed by 11-12%; herbage yield losses within symptom-affected patches were 28-49%. In a further grazing experiment at this site with swards of cvv. Junee and Karridale, BYMV-induced losses determined from symptom-affected patches were 21-29% for herbage and 15-25% for seed. In a grazing experiment with swards of cvv. Denmark and ~ e u r a ' at a third site, BYMV-induced overall herbage yield decreases of 8-12% were still recorded despite extensive BYMV spread to control swards; yield losses within symptom-affected patches were 18-25% for herbage and 35-47% for seed. Seed yield losses were due to decreased seed size (mean seed weight), fewer seeds being produced, or both. Estimates of the effects of different levels of BYMV infection on herbage yields in partially infected grazed swards were obtained for cvv. Denmark, Karridale and Leura by plotting individual quadrat data for herbage dry weights against % symptom-affected plants. Losses increased in proportion to the level of infection, but their magnitude also varied with cultivar and experiment. It is concluded that BYMV infection of subterranean clover pastures is cause for concern, not only as regards herbage yield losses but also as regards depletion of the seed bank, which, when compounded year by year, results in pasture deterioration. Early and prolonged aphid activity, reseeding the pasture with susceptible cultivars, heavy grazing and extended growing seasons are all likely to magnify BYMV-induced losses.

Time application of superphosphate and the yield of pasture on an acid soil.

1961 ◽  
Vol 1 (2) ◽  
pp. 81
Author(s):  
KD McLachlan
Keyword(s):  
Acid Soil ◽  
Total Yield ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
First Year ◽  
Botanical Composition ◽  
Time Of Application ◽  
Relative Ability ◽  
Main Effect ◽  
Earlier Application

Superphosphate was applied in summer (December) or in autumn (March) to an existing mixed pasture of subterranean clover (Trifolium subterraneum L.) and phalaris (Phalaris tuberosa L.), growing on apodsolic soil of p H 5.8. Time of application effects were recorded at the lowest level of applied phosphate. The main effect was on the botanical composition of the pasture. The summer application favoured clover, the autumn one grass. This effect is explained as a change in the relative ability of the species to compete for superphosphate. These results suggest how time and rate of application of superphosphate may be used to manage pasture composition. In the first year, when clover growth was encouraged, the earlier application also increased the total yield of pasture. In the second and third years, changes in the yield of grass were offset by changes ill the yield of clover and the effect of time of application on total pasture yield was not significant.

The interrelation of age, permeability and viability of subterranean clover seeds

1969 ◽  
Vol 9 (40) ◽  
pp. 513
Author(s):  
JA Carpenter
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
The Other ◽  
Small Samples ◽  
Long Term Storage ◽  
Common Effect ◽  
Seed Content ◽  
The Common ◽  
Term Storage

The proportions of impermeable seeds, and the viability of permeable and impermeable seeds were measured in samples of Trifolium subterraneum seed that had been stored in a laboratory for up to 34 years. Viability of permeable seed decreased from 99 per cent after storage for 1 year to 8 per cent after 30 years. On the other hand, all impermeable seeds were viable for 1 to 5 years, and 83 per cent were viable after 30 years. The impermeable seed content of the older seed lots was generally higher than that of the younger ones. This difference was related to the high retention of impermeability of the seeds during storage, and to changes in the severity of threshing methods. The impermeable seed content was also correlated positively but poorly with the viability of both permeable and impermeable seeds, independent of the age of the seed. These associations are probably due to the common effect of the environment on all these variables during seed ripening. A small varietal component in each variable was detected. The implications of these data for the long-term storage of small samples of seed are discussed.

Long term patterns of seed softening and seedling establishment from single seed crops of subterranean clover

1984 ◽  
Vol 24 (125) ◽  
pp. 200 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter ◽  
MJ Palmer
Keyword(s):  
Seedling Establishment ◽  
Subterranean Clover ◽  
Late Summer ◽  
Trifolium Subterraneum ◽  
The Other ◽  
Hard Seed ◽  
Single Seed ◽  
One Year ◽  
Seed Crops

Single seed crops of eight varieties of subterranean clover (Trifolium subterraneum) were grown in swards in four successive years in a medium rainfall environment at Bakers Hill, Western Australia. Measurements were made of seed production, the progress of seed softening within the first two summers, and residual hard seed and seedling numbers after the break of season for up to six successive regeneration years. Patterns of seed softening were also measured in a laboratory oven with a diurnal temperature fluctuation of 60/15�C. Approximately half the seeds of all varieties softened over the first summer and generally well over half the residual seeds softened during the second summer. Up to 18% of seeds of the hardest seeded variety, Northam, and 11% of Geraldton seeds persisted to the end of the third summer as hard seeds. Seed softening patterns showed a significant variety x regeneration year interaction due mainly to a slower rate of softening of Northam seeds relative to the other varieties after the first summer. In six of the varieties, seeds generally softened more slowly in the laboratory than in the field but in the case of the other two varieties this trend was reversed. Nevertheless, ranking of varieties for rate of seed softening was similar in field and laboratory. Seedling establishment ranged from 28 to 100% of soft seeds, depending on the incidence of late summer and autumn rains. It appeared that all varieties in the study would regenerate satisfactorily at densities of more than 15 plants/dm2 after at least one year in which little or no seed is set. Slower rates of softening would probably be desirable in drier regions or in rotation systems involving cropping.

Distribution and abundance of annual legume seeds in the wheatbelt of Western Australia

1995 ◽  
Vol 35 (2) ◽  
pp. 189 ◽  
Author(s):  
JA Fortune ◽  
PS Cocks ◽  
CK Macfarlane ◽  
FP Smith
Keyword(s):  
Western Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Farming Systems ◽  
Annual Rainfall ◽  
Soil Parameters ◽  
Widespread Species ◽  
Legume Seeds ◽  
Clover Seed

The size and composition of pasture legume seedbanks were estimated from 2 surveys on a 460-km west-east transect of the wheatbelt of Western Australia. Survey 1 (in spring) sampled naturalised legumes, and survey 2 (in summer) measured the amount and botanical composition of legume seed from selected sites. Seedbanks were examined in greater detail on 2 farms in the higher rainfall part of the wheatbelt. Survey 2 revealed that mean seedbank size of the poorest 40% of sites (those with 5200 kg seed/ha) was 61 kg/ha, and that 72% of seeds were naturalised clovers. In contrast, the best 60% of sites (those with >200 kg seed/ha) averaged 533 kg seed/ha, of which only 35% was naturalised clover seed, the remainder in both surveys being mainly subterranean clover (Trifolium subterraneum). Mean seed bank size (kg/ha) varied from 359 (survey 2) to 587 (survey 1) and, in both surveys, was poorly correlated with long-term mean annual rainfall and a number of soil parameters. On the 2 farms, seedbank size ranged from 300 to 345 kg/ha (in spring) and from 650 to 740 kg/ha (in summer). Trifolium glomeratum (cluster clover) and subterranean clover were the most widespread species in both surveys. They were present at 35 and 30 of the 57 survey sites, respectively, and at both farms. Most of the subterranean clover collected was cv. Geraldton (22 of 30 sites), the next most frequent cultivar was Dwalganup (6 sites). The currently recommended cultivar, Dalkeith, was found at only 5 sites. Several other legumes including T. tomentosum (16 sites), T. suffocatum (8 sites), Medicago truncatula (7 sites), T. hirtum (4 sites), and M. minima (4 sites) were common, while M. littoralis, M. polymorpha, T. dubium, T. cernuum, T. cherleri, and T. carnpestre were found at single sites. With few exceptions, these are naturalised species and were characterised by flowering times about 20 days later than sown legume cultivars, and seed sizes < 1 mg. The value of these widespread annual legumes to agricultural productivity and sustainability needs to be quantified and their adaptation to wheatbelt farming systems assessed.

Long-term patterns of seed softening in some annual pasture legumes in a low rainfall environment

1992 ◽  
Vol 32 (3) ◽  
pp. 331 ◽  
Author(s):  
GB Taylor ◽  
MA Ewing
Keyword(s):  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Medicago Polymorpha ◽  
Pasture Legumes ◽  
Burr Medic ◽  
Growing Environment ◽  
Simulated Field ◽  
Favourable Environment

Annual rates of seed softening were determined from 4 lines of burr medic (Medicago polymorpha), 1 barrel medic (M. truncatula), and 1 subterranean clover (Trifolium subterraneum) grown at Merredin in the 1 year. Measurements were also made on one of the lines of burr medic grown in 2 other environments, Gnowangerup and Eneabba, in the same year. Burrs were placed on the soil surface at Merredin and the numbers of residual hard seeds determined each year for up to 5 years in this one environment. Patterns of softening of seeds from the same seed populations were also determined in a laboratory oven with a diurnal temperature fluctuation of 60/15�C. In the field, the softening rates of the 5 medics grown at Merredin were similar, averaging 21% of the original seeds each year for the first 4 years. Seeds of the burr medic grown in a more favourable environment at Eneabba were much slower to soften (averaging 14%); hence, hardseededness in these medics was influenced more by the growing environment than by genotype. More than half of the seeds of subterranean clover softened in the field over the first summer, with declining annual proportions thereafter. There were clear differences between the clover and medics in both pattern and rate of seed softening. The lower seed-softening rate of medics than of subterranean clover was more favourable for ley systems involving frequent cropping, especially in low rainfall areas. Treatment of seeds at 60/15�C simulated field softening for subterranean clover well but produced misleading results for the medics.

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